Switch



Dec. 26, 1939. l.. c. coBBETT 2,184,611

SWITCH Filed Dec* 17, 193? 2 Sheets-Sheet 1 K N HJ =`1 Q INVENTOR Leonard C. Cobe y BY t @Zug m, @uw r E s ATTORN Dec. 26, 1939. l.. c. coBBETT 2,184,611,

SWITCH Filed Dec. 1'7, 1937 2 Sheets-Sheet 2 B D T0 F H INSTRUMENT 35 60 2 25 6 70351? 5 T1 E.

75 23 54 67 6, 23 l( vll/MWI Y im .Y Y. Y *Y fr 5/ 3l #3 n E H-hr* "f -1 INVENTOR 23 23 Leonard C'. C'Obbe 55 69 55/ EY 66 54 @3m/M4 @Mm 30 l0 50 70 Il ATTORNE s Patented Dec. 26, 1939 UNITED STATES PATENT OFFICE SWITCH Application December 17, 1937, Serial No. 180,308

10 Claims.

This invention relates to improvements in electrical switch mechanisms and more partieularly to switch mechanisms for connecting in serial manner a plurality of electrical circuits to a common circuit.

While not limited in its application, the switch mechanism of the present invention is particularly designed for use in connection with a multiple-potentiometer recording instrument, for the purpose of connecting into the main circuit oi the instrument and in serial manner a plurality of electrical measuring circuits, each incorporating a thermocouple, whereby the different temperatures measured by the thermocouples may be indicated and/or recorded by the instrument.

Among the objects of the invention may be noted the provision of a switch mechanism for the above and other uses, which is relatively and accurate in its action, which requires a minimum of power for its actuation, and which is self-cleaning and accordingly requires the minimum of attention over long periods of use.

Other objects will be in part obvious and in part hereinafter pointed out in connection with the following disclosure of an embodiment of the invention in detail.

In the drawings:

Figure 1 is a side elevation of the switch mechanism of the present invention, with the enclosing cover therefor being indicated in section;

Figure 2 is an end view of the switch mechanism illustrated in Figure 1, with the cover cut away and shown in section and looking from the left of Figure 1;

Figure 3 is a section along line 3-3 of Figure l;

Figure 4 is an exploded view of the switch mechanism of the present invention, in which the electrical connections are diagrammatically shown; and

Figures 5 and 6 are details in section of certain parts of the switch mechanism.

Referring now to the drawings, wherein like reference characters designate like parts throughout the several views, reference characters I0 and il designate circular supporting discs of insulating material held in spaced relation by the spacing pillars i2 secured between the discs by the through bolts I3, (Figure 4) certain of which may extend through and beyond the leftwise disc i0 (Figure l) to provide mounting for spacing pillars I4 by which the enclosing cover i5 is secured to the assembly as by cap simple in manufacture and assembly, dependable (Cl. 20o-27) screws i6. A circular guard plate i1 is held in spaced relation from the relatively outer face of the disc li as by pillars IB, the cover i5 and the guard plate i1 thus forming a housing within which is contained the discs l0 and Il and the switch parts carried thereby.

Each of the discs iii and Il carries on its relatively outer face a spring contact assembly connected to one side of a common circuit, and a plurality of individual spring contact assemblies, each of which is connected to one side of a particular measuring circuit. Preferably the plurality of spring contact assemblies connected to the measuring circuits are arranged intermediate the outer faces of the discs and the two spring contact assemblies connected to the common circuit, and accordingly the latter assemblies will be referred to as the outer contact assemblies and the plurality of assemblies connected to the measuring circuits will be referred to as the under contact assemblies.

Referring now to the outer contact assembly as carried by the disc Hl and as illustrated in Figure 2, this is preferably comprised by two stampings 20, 2| of spring metal, the arcuate body portions of which extend along the periphery of the disc I0. The stampings 20, 2| are electrically connected by a jumper bar 22 and are each provided with a plurality of inwardly directed switch blades 23 which extend along converging arcs which intersect the arc of the peripheral or body portion of the stampings, the inner free ends of the blades lying onra circle struck from the center of the disc Il). The curvature of the blades increases their length and thus their flexibility, with the result that they may be iiexed with a. minimum oi force.

The body portions of the stampings 20, 2l are secured to and spaced from the relatively outer face of the disc IU by spacing bushings 24 through which suitable securing means such as rivets or grommets 25 may extend. The number oi' the switch blades corresponds to the number of the measuring circuits and, in the construction shown for purpose of illustration, are eight in number whereby to provide means for connecting the eight thermocouples A, B, C, D, E. F, G, H to a common circuit which is a circuit to the instrument (not shown). Accordingly the blades are designated 28A, 23B, 28C, 22D, 23E, 23E', 23G, 23H.

The stampings 2B, 2l are of conductive metal, and the entire contact assembly is electrically connected to a conductor 26 leading to the instrument through a tang 28 secured to the stamping 23 and soldered or otherwise connected to the conductor, which passes through a suitable aperture 29 formed in disc I3. The switch blade portions 23 of the assembly are so mounted as to be flexible relatively outwardly, but are inwardly flexed. i. e., towards the face of the Adisc I3, such flexing being limited by means of inwardly projecting spacer pins 33 carried by each of the blades intermediate their ends. Referring to Figure 6, each blade at its inner end carries a contact 3l which extends from the under face of the blade and is disposed generally transversely of the length thereof. Preferably the contacts are each constituted by a length of wire of good conductive and wear resisting metal such as platinum-iridium alloy. The wire is bent into U-shape, with its legs set into holes provided in the end portion of the blade, and is thereupon secured to the blade as by soldering, as indicated in Figure 6.

The disc II carries on its relatively outer face a switch contact assembly substantially identical but transposed with respect to the assembly just described, and is constituted by the stampings 23', 2I', jumper bar 22', and the switch blades generally designated 23'. and individually referred l to as 23A', 23B', 23C', 23D', 23E', 23E', 23G', 23H', this assembly being connected to the other lead 21 to the instrument through the tang 28'.

Referring now to the under spring contact assembly carried by the disc I3, this is constituted by eight spring metal stampings generally indicated at 35 to provide relatively long switch blades 35A, 35B, 35C, 35D, 35E, 35F, SEG, 35H, each extending from a base portion 36 fixed to a face of the disc by securing screws 31 threaded into the holding blocks 33 carried on the other face of the disc. The blade portion of each assembly extends inwardly but not radially of the disc I3, whereby its length is increased, and in such direction that its free end portion underlies the end of a converging switch blade of the outer assembly. The under contact assemblies are, like the outer assembly, of conductive metal and their base portions each are provided with an exten sion to which the leads 43A, 43B, 43C, 43D, 43E, 43F, 43G, 43H, to the thermocouples are connected, these leads passing through apertures 4I in the disc I3.

Although the switch blades 35 normally lie against the outer face of the disc I3, their free ends may be readily exed outwardly, to engage against the free ends of the blades 23, due to their spring metal construction and their substantial length. Each of the switch blades 35 carries on its relatively outer face a contact 43 similar in construction to the contact 3|, and extending in the direction of the length of a blade. Thus, by reference to Figures 5 and 6, the contacts 3| carried by the switch blades of the outer assembly are substantially at right angles to the contacts 43 carried by the under switch blades, and the spacing between the assemblies is such that the contacts are normally separated.A With the blades 23 and 35 flexing about axes which are angularly inclined as shown in Figures 2 and 3, it will be seen that when one of the switch blades of an under assembly is iiexed relatively outwardly to engage against and to cause outward flexure of the related blade 23 of the outer assembly, the contacts 3l, 43 engage each other with a wiping action, with the result that the contacts are essentially self-cleaning. Further,

by reason of their circular sections and intersect` tially point contact which is maintained throughout the period of their engagement, irrespective of variations in the force required for their actuation, whereby the electrical contact made is substantially the same for each successive switch closing.

Disc I I carries an under contact assembly substantially similar but transposed with reference to the under assembly as carried by the disc I3 and comprises the switch blade elements generally referred to as 35 and individually designated 35A', 35B', 35C', 35D', 35E', 35B", 35G', 35H'. The latter assemblies are connected through leads 4IA, 4IB, 4IC, 4ID, 4IE, 4IF, 4IG, 4IH, to the other side of the several thermocouples.

Considering now the means for actuating the switch in such manner as to connect successively the thermocouples into the common circuit 26, 21 of the instrument, reference is had to Figures 4 and 5 wherein 53 designates a rotor` element arranged between discs I3, I I. The rotor 53 is driven by a spindle 5I which extends through a fixed bearing bushing 52 threaded into the disc I I, the spindle also extending through a hubbed bushing 53 threaded into the rotor, the spindle being secured to the bushing 53 as by a set screw 54. Spindle 5I through its gear 55 (Figure 1) is driven intermittently by any well known step-by-step movement and thus imparts periodic movement to the rotor 53. The arrangement is such that, at each partial rotation of the spindle 5I, the rotor 53A is driven throughout an angle of 45, whereby any one complete revolution of the rotor makes eight dwells, thus to correspond to the number of thermocouples.

On the face of the rotor 53 adjacent the disc I3 is arranged a camming device in the form of a conical head 63, the shank 3l of which extends into the rotor and is secured by the nut 32. Arranged on the other face of the rotor, i. e., the face adjacent the disc II, and disposed from the head 33 is a conical head or cam 34 whose shank 65 is similarly held in the rotor 53 by a nut 66.

The head 63 is adapted, upon rotation of the rotor 53, to engage successively a series of eight balls 61 carried in equidistantly spaced ball pockets 6B in the disc I3, with the head 64 similarly engaging a like series of balls 69 carried in ball pockets 'I3 of the disc II. The ball pockets are formed by a circularly arranged series of apertures in each of the discs I3, I I, the pockets being disposed to underlie the crossed ends of the switch blades of the contact assemblies. The arrangement and proportioning of the parts is such that the balls 31 are normally loosely held in the pockets 68, being maintained therein by the under face of the spring blades 35 and by the adjacent face of the rotor 53. Similarly the balls B9 are loosely carried in the pockets 13 of disc II. However, when the rotor 53 moves to a position in which dametrically opposed heads engage a pair of balls 61, 69, the latter are forcedrelatively outwardly by camming action of -the heads against the overlying spring blades 35, 35', of the under assemblies and to a degree causing the free ends thereof to move against and iiex outwardly the overlying spring blades 23, 23', of the outer assemblies. The contacts 43 and 3I of the so actuated spring blades thus engage with a wiping action, and in so doing electrically connect a pair of diametrlcally opposed under assemblies with the outer assemblies of the discs I3, II.

Due to the opposed relation of the heads 53, 64, it will be seen that as contact is made between one set of contacts 3|, 43 of the assemblies carried by the disc IIJ, contact is simultaneously made between an opposed set of contacts of the switch assemblies carried by the disc l I. As the making of contact between one set of contacts 3i, 43 as carried by disc lli connects one of the instrument conductors with one side of a thermocouplefthe arrangement herein provides that the simultaneous making of contact between the set of opposed contacts 3|, 43 as carried by the disc Il connects the other instrument conductor to the other side of that thermocouple, and consequently a thermocouple circuit is connected to the common instrument circuit.

Thus if we assume that the head 60 through ball 61 (Figure 4) is pressing switch blade 35A outwardly so that contact is established between switch blade 35A and the related switch blade 23A of the outer contact assembly, instrument lead 26 is electrically connected with the conductor MIA which forms one side of the circuit of thermocouple A. Simultaneously head 64 engages ball 69 to make contact between switch blades 23A' and 35A', thus to connect the conductor MA, being the other side of the circuit of thermcouple A, with the instrument lead 21. The circuit of thermocouple A is now connected to the instrument circuit whereby the temperature measured by the thermocouple A may be indicated and/or recorded by the instrument. As the rotor 50 thereafter moves from its dwell position, the circuit of thermocouple A i's disconnected from the instrument and upon its next period of dwell the rotor 50 connects the circuit of thermocouple B with the instrument circuit. Accordingly, as the rotor 50 makes one complete rotation the circuits of the thermocouples A, B, C, D, E, F, G, H, are serially connected in the instrument circuit for the time period of each dwell of the rotor as established by its intermittent drive.

The apices of the cone-shaped heads 6I), 6l are cut away to provide flattened surfaces and one such surface is drilled as at 15 (Figure 5), to provide a centering seat for the balls 68. Hence, as the rotor comes to a position of rest with the head 60 engaging a ball 68. the ball is centered on the head and is thereafter maintained centered for the particular dwell period. However, the arrangement is such that the ball may readily unseat itself as the rotor commences its further moiment, so that a quick separation of the contacts 3|, 43 results and a minimum of force only is required to initiate the further movement of the rotor.

When the switch above described is used as a. two-point or four-point switch as, for example, with a two or four record potentiometer recorder, the leftwise disc ID and its associated parts' may be eliminated. Referring to Figures 4 and 5, with such an arrangement, however, the coneshaped head lili is turned around to face in the same direction as the cone-shaped head 64 so that both cone-shaped heads are supported on the balls B9. With this operation, too, the connector 22' is eliminated and the stampings 20 and 2|' then become the plus and minus connectors to the instrument.

As many changes could be made in carrying out the above constructions, without departing from the scope of the invention, it is intended that all matter contained in the above descrip'- tion or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

l. In a switch mechanism, in combination, a supporting base, a iirst contact assembly secured to the base and having a plurality of flexible convergently extending switch blades terminating on a common circuit with their longitudinal axes tangential thereto, a plurality of other contact assemblies secured to the base and providing flexible convergently extending switch blades spaced from switch blades of said first assembly and terminating on the common circle with their longitudinal axes tangential thereto and their convergent ends positioned opposite the convergent ends of the switch blades of the iirst mentioned assembly, means for moving the ends of one of said groups of blades into engagement with opposed ends of the other group of blades. and means for periodically engaging and actuating said blade moving means.

2. In a switch mechanism, in combination, a supporting base, a iirst contact assembly secured to the base and having a plurality of flexible convergently extending switch blades terminating on a common circle with their longitudinal axes tangential thereto, a plurality of other contact assemblies secured to the base and providing flexible convergently extending switch blades spaced from switch blades of said first assembly and terminating on the common circle with their longitudinal axes tangential thereto and their convergent ends positioned opposite the convergent ends oi' the switch blades of the first mentioned assembly. means for moving the ends of one of said groups of blades into engagement with opposed ends oi. the other group of blades, means for periodically engaging and actuating said blade moving means. and means effective between the ends of each blade of one of said groups of blades and interposed between said blades and said base to limit the extent of movement of said blades toward said base.

3, In a switch mechanism, in combination. a supporting base, an outer contact assembly carried by the base and spaced from a face thereof, the assembly including a body portion secured to the base and a plurality of flexible switch blades extending inwardly and terminating on a common circle, a plurality of under contact assemblies each related to but normally spaced from a switch blade of the outer assembly, the under assemblies each including a base portion secured to the base and a flexible switch blade extending inwardlv and terminating on the common circle whereby the ends thereof underlie the ends of the switch blades oi the outer assembly, the base being provided with a series of apertures arranged on the common circuit, each of which registers with a set of under and outer switch blade ends, means operatively disposed in said apertures for moving the ends of the blades of one of said assemblies into engagement with the adjacent ends of the blades of the other assembly, and means for periodically engaging and actuating said lastnamed means.

4. In a switch mechanism, in combination, a supporting base, an outer contact assembly carried by the base and spaced from a face thereof, the assembly including a body portion secured to the base and a plurality of flexible switch blades extending inwardly and terminating on a common circle,` a plurality of undencontact assemblies each related to but normally spaced from a switch blade of the outer assembly, the under assemblies each including a body portion secured to the base and a flexible switch blade extending inwardly and terminating on the common circle whereby the ends thereof underlie the ends of the switch blades of the outer assembly the base having a series of apertures arranged cn the common circle, each registering with a related pair of under and outer blade ends, a ball loosely carried in each of said apertures and adapted upon actuation to'move the end of an under switch blade into engagement with the end of an outer switch blade, and means for periodically engaging and actuating the balls.

5. A switchmechanism comprising in combination a supporting member, an outer contact spring blade carried by said member and spaced from a face thereof and having a free end, an inner spring blade carried by said member and having a free end overlapping the free end of the cuter blade, said supporting member having a hole therethrough and a ball loosely carried in said hole, and means to force the ball against said under blade including a rotor having a ball moving portion presenting a centering seat toward said ball to engage the same and hold it in blade actuating position.

6. In a switch mechanism, in combination, a supporting disc, an outer contact assembly carried by the disc and spaced from a face thereof, the assembly including a body portion secured to the disc along its periphery and a plurality of ilexible switch bladesextending inwardly therefrom and terminating on a common circle, a plurality of under contact assemblies each related to but normally spaced from a switch blade of the outer assembly, the under assemblies each including a base portion secured to the disc adjacent its periphery and a exible switch blade extending inwardly therefrom and terminating on the comomn circlewhereby the ends thereof underlie the ends of the switch blades of the outer assembly, the disc being provided with a series of apertures arranged on the common circle, each of which registers with a set of under and outer switch blade ends, means operatively disposed in said apertures for actuating the ends of the blades of the under assemblies into engagement with the overlying ends of the blades of the outer assembly, and periodically operating means for actuating in serial manner said last-named means.

'1. In a switch mechanism, in combination, a supporting disc, an outer contact assembly carried by the member and spaced from a face thereof, the assembly including'a body portion secured to the disc along its periphery and a plurality of flexible switch blades extending inwardly therefrom and terminating on a common circle. a plurality of under contact assemblies each related to but normally spaced from a switch blade of the outer assembly, the under lblades of the outer assembly, the disc having a series of apertures arranged on the common circle, each registering with a related pair of under and outer blade ends, a ball loosely carried in each of said apertures and adapted upon actuation to move the end of an under switch blade into engagement with the end of an outer switch blade, and periodically operating means `for actuating the balls in serial manner.

8. A switch mechanism comprising, in combination, a supporting member, an outer contact spring blade carried by the member, spaced from a tace thereof and having a free end, an inner spring blade carried by said member and having a i'ree end overlying the free end of the outer blade, said member having a hole therethrough and a ball loosely carried in said hole, a rotor, and a dished head mounted on said rotor. said rotor being rotatable to move the head thereof into engagement with said ball to torce the same against the under side oi' the free end o! the under blade to move the under blade into contact with the outer blade, the dished portion of said head acting to center the bail on the head.

9, Switch mechanism comprising in combination opposed spacedcontact blades one of which has a contact'portion yieldingly movable toward a contact portion of the other, a rotor, a support for a ball, a ball loosely retained by said support between and in rolling contact with a portion of one of said blades and a portion of said rotor, and means on the rotor for imparting blade actuating movement to the ball.

10. Switch mechanism comprising in combination opposed spaced contact blades, one of which has a contact portion yieldingly movable toward a contact portion oi the other, a rotor, a blade pushing element loosely supported between said yieldingly movable contact portion of one of said blades and said rotor, and a. camming element on the rotor for engaging and actuating said blade pushing element, one of said elements having a centering seatl for engagement with the other o! said elements.

LEONARD C. COBBE'II'.

CERTIFICATE 4OF- CORRECTION. Patent VNo.- 2,1`8lh611. December 26, 1959.

LEONARD c. coBBETT.

It is hereby certified lthaterror appears in the printed specifi cation of the above numbered 4patent requiring correction as follows: Page5, second column, lines 6 'and 5'?, .claims 1 and 5 respectively, for the word "circuit" read circle; and that the said Letters Patent shouldbe read with this correction therein that the s ame may conform to the record of the case .in the Patent Office.

Signed and sealed this4 50th day of April, A. D. 19140.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

